1. Field of the Invention
The present invention relates to a motor, and more particularly, to a single phase induction motor capable of reducing a consumption electric power and reducing noise by installing a magnet unit in a body of an induction motor.
2. Description of the Related Art
Generally, an induction motor is an alternating current having no commutator, and one of a rotor and a stator is connected to a power and the other is operated by induction.
FIG. 1 is a longitudinal section view showing an inner part of a single phase induction motor in accordance with the conventional art, and FIG. 2 is a sectional view taken along line A-A′ of FIG. 1.
Referring to FIGS. 1 and 2, the conventional single phase induction motor comprises: a motor body 1 serving as a casing; a stator 2 arranged along an inner circumferential surface of the body 1; an AC squirrel cage rotor 3 rotatably arranged at a center portion of the stator 2; and a rotation shaft 4 around which the rotor 3 is rotated. Herein, the rotor 3 is constructed to always maintain a constant interval with the stator 2.
Between the rotation shaft 4 and the motor body 1, a rotation shaft bearing 4a is installed so that the rotation shaft 4 can not be influenced by the motor body 1.
The stator 2 is formed of a plurality of laminated silicon steel sheets, and is provided with a plurality of coil winding protrusions 5 at an inner circumferential surface thereof. A plurality of slots 6 are formed with a constant interval between the coil winding protrusions 5, and a coil 7 is wound on said each coil winding protrusion 5.
The rotor 3 is also formed of a plurality of laminated silicon steel sheets, and is provided with conductor bar holes 8 in the laminated sheets at a constant interval. Conductor bars 9 formed of Aluminum are inserted into the conductor bar holes 8, and end rings 10 are connected to upper and lower end portions of the conductor bars 9.
Operations of the conventional induction motor will be explained as follows.
If a power is applied to the coil 10, a rotating magnetic field is generated by a current of the coil 10 and an induced current is generated at the conductor bars 9.
By an interaction between the generated rotating magnetic field and the induced current, a rotation torque is generated at the rotor 3 and the rotation torque is outputted through the rotation shaft 4.
However, in the conventional induction motor, both a current for generating the rotating magnetic field and an induced current generated from the rotor are supplied through a coil connected to an external power source. At this time, by a primary copper loss generated from the stator coil and a secondary copper loss generated from the conductor bars of the rotor, loss of current is increased and thereby efficiency of the motor is decreased.